1. Field of the Invention
My invention relates to inflatable tents and similar temporary enclosures, and more particularly to structures of this type in which a sheltering cover is supported by an inflatable framework.
2. Prior Art
A wide range of inflatable structures appears in the prior art. At one end of this range, and most remote from the concepts of the present invention, are devices in which the tent sheathing or sheeting itself is inflatable, usually in a cellular arrangement. The prototypical art at this end of the range may be exemplified by U.S. Pat. No. 4,000,585 to Denaro, wherein an inflated cellular sheeting is supported by a conventional hardware frame--though with novel means of attachment to the ground. U.S. Pat. No. 3,540,170 to Flowers discloses a configuration in which substantially the entire sheathing is cellularly inflatable to form a self-standing frustoconical enclosure.
Near the center of the range of prior-art inflatable structures are enclosures in which the sheathing is unitary with spaced-apart inflatable frame cells. Typically the sheathing is of two-ply construction, in which the two plies are cemented or fused together everywhere except where the frame elements are desired; the unlaminated areas are simply inflated to form "ribbing"--frame elements. In U.S. Pat. No. 3,457,684 to Wood, this concept is shown embodied in such configurations as a pup-tent shape, a domed-vertical-cylinder or igloo shape, and a horizontal-half-cylinder or Quonset-hut shape. In U.S. Pat. No. 2,938,526 to Harrison et al., the same concept is shown embodied in a one-piece pyramid formed of several tetrahedral sections--with inflated rib cells along five of the six edges of each tetrahedron, and sheathing on two of the four sides of each tetrahedron; the entire pyramid may be adjusted in height by controlling (with a stretched rope or cable) the lateral distance between the bottom tips of the tetrahedra, which touch the ground.
At the other end of the range of prior-art devices, and most closely related to the present invention, are configurations in which the frame members are at least initially separate from the sheeting--though the sheeting may be strapped, glued or fused to the frame members subsequently. U.S. Pat. No. 3,899,853 to Wertman discloses sheeting having spaced-apart linear pockets, which accept simple inflatable cylindrical tubes to form parallel arched ribs of a Quonset-hut-shaped enclosure. U.S. Pat. No. 2,591,829 To Katzenmeyer et al. discloses frame segments united or jointed to produce an arched frame. A purported improvement to this is disclosed in U.S. Pat. No. 2,752,928 to Barker, wherein the frame members are preformed--that is, prearched--to prevent buckling and thus weakness of the frame. Barker shows parallel spaced tube arches with "lodgepole" tube sections connecting the tops of the arches.
The inflatable enclosure devices mentioned in the foregoing paragraphs mimic construction of hard-frame buildings. That is, they use the same structural elements and configurations as conventional structures made of wood or metal, merely substituting inflatable materials of construction for the conventional sheeting and framing materials. These prior devices thereby fail to realize the full potential for economy, sturdiness, ease of maintenance, safety, and speed of inflation and deflation which can be achieved through consideration of the basics of inflatable structures per se.